The objectives of this study are: 1)to determine if the prophylactic administration of rPAF-AH decreases in incidence and severity of post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis in a dose-dependent manner. 2)to evaluate the cost-efficacy of rPAH-AH when administered prophylactically to prevent post-ERCP pancreatitis. 3)to characterize the safety and pharmacokinetic behavior of rPAH-AH after intravenous administration in patients scheduled to undergo ERCP.